/Engine/Plugins/Runtime/MeshModelingToolset/Source/MeshModelingTools/Public/DrawPolygonTool.h
Notify Target device position has changed but a click sequence hasn't begun yet (eg for interactive previews)
virtual void OnBeginSequencePreview ( const [FInputDeviceRay](API\Runtime\InteractiveToolsFramework\FInputDeviceRay) & ClickPos )